1. Field
This invention relates to battery systems and battery chargers. More particularly, this invention provides for a temperature maintained battery system containing a battery, battery charger and heating and cooling devices which is particularly suitable for use with vehicles.
2. State of the Art
In many applications batteries are used as a temporary emergency source of power. For example, in certain kinds of vehicles, such as aircraft, batteries act as a source of power for starting engines and as an emergency source of power in the event the generator typically associated with the engine of the vehicle fails. For such applications, it is important to return the battery to and maintain it in a fully charged condition after use. However, it is well known that charging a battery to and maintaining it in a fully charged condition is a multi-faceted problem involving many factors. For example, battery type, battery age and useful life, available charging power, physical environment, and battery capacity are just some of the factors to be considered in selecting not only the battery to be used but also the battery charger to optimally charge and recharge the battery.
In some applications, the vehicle may experience a wide range of temperatures from very cold to very hot. Some vehicles, such as automobiles, tanks, bulldozers and the like may experience temperatures during certain seasons from well below 0.degree. F. to well above 100.degree. F. in other seasons. An aircraft may experience such temperature ranges over a very short period of time. For example, on a runway it may experience temperatures substantially above 100.degree. F. Yet, when airborne it may be in an ambient temperature environment which may be substantially below -50.degree. F. depending on season and altitude.
Batteries and charging systems hereinbefore known have not been particularly adaptable for use in environments where temperature ranges are from well below 0.degree. F. to well above 100.degree. F. As known to those skilled in the art, battery capacity, battery age, battery useful life and similar battery characteristics are all affected by ambient temperature environments. Typically, batteries presently used in vehicles that do suffer wide ranges of temperature by virtue of their environment, are selected to have a battery capacity and other battery characteristics relating to average conditions or to be within acceptable minimum limits under the full range of anticipated conditions. Accordingly, battery weight, battery capacity and similar characteristics may be at a bare minimum under certain-adverse circumstances and may even fall below minimum desired characteristics in certain ambient environmental conditions which fall outside of those anticipated. Further, during normal operations, the battery may be oversized so that the weight and cost thereof are undesirable.
It is also known to those skilled in the art that battery chargers generate heat during charging operations. Accordingly, it has become a practice to locate charging equipment somewhat remote from the battery itself because the heat generated by the charger may adversely affect the battery. In some circumstances, this generates maintenance problems as well as weight problems by virtue of the need to provide two separate components. That is, a battery itself comprised of a plurality of cells must be manufactured and located in a vehicle separately remote from a separately designed and contained battery charging unit. Excessive weight, cost and maintenance problems may adhere by virtue of separate construction and installation.
Battery heating and cooling has a been a technique employed in the art to provide more acceptable tolerances for battery characteristics. Known battery cooling techniques include fluid water-cooling type systems for large capacity type batteries such as those which may be found on submarines. Known heating methods include positioning the battery near the vehicle engineer or putting heaters for heating air supplied to ventilate a battery. However, a practical vehicle battery relatively small in size which has automatic heating and cooling is unknown. That is, there is no known system is which a battery charger and a battery have been combined into one integral system which includes cooling and heating means to provide a unitized easily removable lower weight unit (relative to capacity and temperature environment) for use in vehicles.